A. Field of the Invention
The present invention relates to an Internet/telephone adapter device and method, especially to an adapter device and method which can detect the communication types of an incoming call, thereby to automatically switch the communication linkage to a corresponding type of communication without manual operations.
B. Description of the Prior Art
Internet telephony provides the telephone service via Internet. The users can use the bandwidth of the Internet to transfer voice signals as if they are talking over a telephone line. To provide a better QoS, users can subscribe to an Internet Service Provider (ISP). The ISP will provide the user with a special equipment which can be an add-on box to the telephone set. Then, with the equipment, the user can use a dedicated communication line to connect to the ISP server and then use the dedicated communication line for telephone service. The advantage for this Internet telephony service is that it can save lots of money for the users especially when they usually make lots of overseas or long distance calls. However, the disadvantage is that the subscription fee for the dedicated line is still an investment.
Another approach which costs less is using a PC and a MODEM at home to connect to the Internet via a regular telephone line. The user must run a software program on the computer for voice processing so that the voice signals can be processed as packets to be transferred over the Internet. The hardware implementation for the personal computer includes simply a microphone, a speakerphone, and a sound card. For this approach, both caller and callee must know how to implement the software and hardware operations on the computer, and also how to dial-up to the Internet using the MODEM. For users who are not familiar with computer operations, this approach is not feasible. Moreover, the voice quality on the Internet is also very difficult to control because of the heavy traffic flow on the Internet.
Currently, a standalone adapter device is available on the market for providing Internet telephony. The adapter device is like an add-on device to the telephone set. Both the caller and the callee need to implement the adapter device to their telephone sets so that they can choose to make a call via the Internet or the PSTNs (Public Switched Telephone Networks). The disadvantage for this adapter device is that it cannot automatically determine the communication type of an incoming call. Consequently, the caller must make a regular telephone call to the callee first and tell the callee to switch the adapter device to the Internet mode before they can actually talk over the Internet. The standalone adapter device does not need subscription fee for a dedicated communication line. However, the disadvantage is that a notice call is always required. Moreover, if someone else calls right after the notice call and the callee answers the phone, then the caller at the remote site will have to wait and wonder if there is anything wrong with the adapter device or the Internet.
The primary object of the present invention is to provide an Internet/telephone adapter device which can detect the communication type of an incoming call, and automatically switch the communication linkage to a corresponding communication linkage without manual operations, thereby to make the Internet telephony more convenient to use.
Another object of the present invention is to provide a user-friendly Internet/telephone adapter device to add on to a regular telephone set so that the users can save money on long distance calls or overseas calls by fully utilizing the bandwidth of the Internet.
In accordance with the present invention, the Internet/telephone adapter device mainly comprises: an interface module, a hybrid circuit, a modulation/demodulation means, an auto-detecting means, a digital signal processor, and a CPU. The auto-detecting means provides a mechanism to detect the communication type of an incoming call by means of the feature rings. The feature rings have a predetermined feature distinguishable from non-feature rings. Whenever the auto-detecting means determines the communication type of the incoming call, it sends a control signal to CPU. In response to the control signal, the CPU will automatically switch the linkage to the Internet or to the PSTNs without further human operations. More particularly, the operation for the adapter device is very easy. For the callee, he can answer any phone call without worrying about whether it is an Internet call or a conventional phone call. For the caller, he only need to press a predetermined function key before dialing the callee""s phone number.